I'm currently in the Midwest so 93 oct is hard to find. I tried 91 oct E0 and it performed as well as 93 oct E15 (same mpg). If there was any difference in performance I didn't notice. Is it worth the effort trying to find it? Not IMO, since our cars won't suffer the side effects of E15 like older cars do.
I have been using
Archoil AR6200 for months now so maybe if I didn't I would have noticed a bigger difference.